Here are a few ideas, some that I've used and some that others have used.
I'm Okay Now
Often, at the beginning of the year, kids will come into the classroom uncertain and maybe even unhappy. And they are unhappy when parents leave. Often the child calms down quickly but parents are still probably thinking about the unhappy child they left. Take a photo of the child happy and engaged in the classroom. Send (via text or mail) that photo to the parents. The teacher who told me about this said they try to send the photo as soon as possible after parents have left. Parents have peace of mind knowing the child is happy and no longer upset. And you have made a positive connection with parents, showing them you understand and want to help.
First Days
It's always fun to take photos of the child's first day in a new classroom. I know many teachers that post these photos or save them for an end-of-the-year activity/companion to end-of-year photo. I'm thinking that making a simple "first days" card with the photo and mailing (or sending electronically) to parents within the first week makes a simple connection and gives parents insight to what the children are doing in the classroom.
Favorites or Achievements
I take a lot of photos every week. I usually take candid shots, capturing the children working and playing. But sometimes, kids will complete something or have fun doing something. They ask me to take a photo. A building structure. A pretend restaurant chef. Using a favorite item in the room. More than once, I've had children ask me to send the photo to parents on Facebook or email. Making these small connections and sharing a little of what the child (and you as the teacher) experienced will build significant bridges with parents.
Portfolios
Take photos of children doing different things in the classroom. Take photos of art projects, constructions, significant play, and writing. Place these in an electronic portfolio or print copies for the child's paper portfolio. Use these when talking to parents in conferences or answering questions about a child's progress. Photos can capture nonpermanent things or preserve information that could be easily lost.
Memories
We use photos as gifts. Every Christmas we make wonky frames with hot glue guns - and include a photo of the child. Several years I have made books from our activities. (I bring my laptop and the children create the text for the pages.) I print a copy for our classroom. But I have included a PDF of the book on CDs for parents/families. Also on each CD, I pull several photos of the child from throughout the year. Parents have enjoyed these CDs in the past. One mom told me they had looked at the photos for several years (off and on) after leaving our class. (Personal note: I haven't done this in the past couple of years; I need to do it again!)
Print photos on card stock and make personalized postcards. Jot a simple note, address the card, and drop it in the mail. (Kids and parents love to get personal notes mailed to them!) Or send a photo of yourself as a postcard to introduce parents and kids to you as the new teacher.
What ways have you used photos (either printed or electronically) to connect with parents and build relationships?